Drying Characteristics of Eucalyptus urophylla × E. grandis with Supercritical CO2

Supercritical CO2 (ScCO2) is a drying medium with excellent solubility and mass transfer efficiency. Supercritical CO2 drying (SCD) can remove the water of wood rapidly and prevent a change of microstructure caused by capillary tension in the drying process. In this study, Eucalyptus urophylla × E. grandis specimens with lengths of 50 and 100 mm were dried with ScCO2. Conventional kiln drying (CKD) and oven-drying (OD) were used as control. After 1 h, the drying rate, shrinkage, moisture distribution, drying stress were measured to explore the influence of drying methods and specimen length for drying characteristics during the early drying stage. The results showed that compared with CKD and OD, water removal was the fastest under SCD, and the drying rate was nine times of CKD and one time of OD. The shrinkage of SCD was the lowest among the three drying methods. Moisture distribution of SCD and OD was uneven. The drying stress of SCD was relatively high, the drying stress index of it was almost five times of CKD and three times of OD. Regardless of the drying method, shorter specimens had a shorter drying period but greater drying defects than the long specimens.

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Comparison of Supercritical CO2-Drying, Freeze-Drying and Frying on Sensory Properties of Beetroot

Foods ◽

10.3390/foods9091201 ◽

2020 ◽

Vol 9 (9) ◽

pp. 1201

Author(s):

Nikola Tomic ◽

Ilija Djekic ◽

Gerard Hofland ◽

Nada Smigic ◽

Bozidar Udovicki ◽

...

Keyword(s):

Supercritical Co2 ◽

Freeze Drying ◽

Sensory Quality ◽

Quality Parameters ◽

Acceptance Testing ◽

Drying Methods ◽

Promising Alternative ◽

Supercritical Co2 Drying ◽

Negative Effect ◽

Drying Technology

The aim of this study was to compare the sensory quality and acceptance of dried ready-to-eat beetroot snacks as a result of different drying methods applied: supercritical CO2-drying (scCO2-drying), frying, and freeze-drying. Descriptive sensory analysis, quality rating (10 assessors), and consumer acceptance testing (n = 102) were performed. Mean overall quality scores within the range of “very good” quality were found only in non-precooked scCO2-dried samples which were characterized by typical magenta color, low level of shape and surface deformations, pronounced brittleness and crispiness, and good rehydration during mastication. The other samples were in the range of “good” quality. The pre-cooking step before scCO2-drying negatively influenced the sensory quality parameters, particularly appearance. Around 60% of tested consumers showed a preference for the fried and non-precooked scCO2-dried samples. The drivers of liking were mostly related to the characteristics of the product, which was salted, fried, and crispy, with an oily and overburnt flavor, i.e., the product most similar to commercial potato chips products. Freeze-drying had a negative effect primarily on appearance and flavor. According to the sensory evaluation conducted, direct scCO2-drying without a pre-cooking step showed itself as a promising alternative drying technology in the production of dried beetroot snacks.

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Effect of Supercritical CO2 Drying on Moisture Transfer and Wood Property of Eucalyptus urophydis

Forests ◽

10.3390/f11101115 ◽

2020 ◽

Vol 11 (10) ◽

pp. 1115

Author(s):

Lin Yang ◽

Honghai Liu

Keyword(s):

Moisture Content ◽

Supercritical Co2 ◽

Moisture Transfer ◽

Content Distribution ◽

Wood Property ◽

Drying Rate ◽

Extractive Content ◽

Moisture Content Distribution ◽

Bordered Pits ◽

Supercritical Co2 Drying

Wood dried using supercritical CO2 has unique properties because water is removed directly from the cell lumens through the cycling between supercritical and gas phases. Eucalyptus urophydis green wood was dried by supercritical CO2 at 50 °C and pressure of 10, 20, and 30 MPa; the effect of supercritical CO2 drying on moisture content distribution and transfer, as well as the permeability and extractive content of the wood, was investigated. The results showed that the supercritical CO2 drying rate was high, showing the highest drying rate at 20 MPa and the lowest at 10 MPa. Drying rate increased with pressure below 20 MPa in this study; drying rate represented no positive relation to pressure over 20 Mpa. Moisture content distribution was more uneven in the low-pressure drying conditions and in the middle transverse section of the specimens. The moisture content gradient in tangential was greater than that in longitudinal, especially for the drying of 10 MPa, indicating that water was removed mainly in the former direction of wood. More extractives were removed from wood at higher pressure during supercritical CO2 drying. Bordered pits were broken up more at higher pressure conditions. The decreased extract yields and increased amount of opened bordered pits increased the permeability of the wood after supercritical CO2 drying.

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Supercritical CO2 drying of food matrices

Proceedings of 21th International Drying Symposium ◽

10.4995/ids2018.2018.7753 ◽

2018 ◽

Author(s):

S. Spilimbergo ◽

A. Zambon ◽

T. M. Vizzotto ◽

G. Morbiato ◽

M. Toffoletto ◽

...

Keyword(s):

Supercritical Co2 ◽

Supercritical Drying ◽

Microbial Inactivation ◽

Process Conditions ◽

Drying Methods ◽

Drying Process ◽

Promising Alternative ◽

Supercritical Co2 Drying ◽

Conventional Drying ◽

Drying Efficiency

This work explore the use of supercritical CO2 drying as alternative technique for the obtainment of pasteurized and high quality dried product. Several tests were conducted on animal, vegetable and fruit matrixes in order to investigate the effectiveness of SC-CO2 drying process at different process conditions. Design of experiment was performed to find the optimal process conditions for vegetable and fruit matrices, using the final water activity of the products as key indicator for the drying efficiency. The inactivation of naturally present microorganisms and inoculated pathogens demonstrated the capability of SC-CO2 drying process to assure a safe product. Moreover, retention of nutrients was compared with conventional drying methods. Results suggest that supercritical drying is a promising alternative technology for food drying. Keywords: supercritical drying; carbon dioxide; food drying; microbial inactivation

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Effect of Temperature and Pressure of Supercritical CO2 on Dewatering, Shrinkage and Stresses of Eucalyptus Wood

Applied Sciences ◽

10.3390/app11188730 ◽

2021 ◽

Vol 11 (18) ◽

pp. 8730

Author(s):

Lin Yang

Keyword(s):

Residual Stress ◽

Supercritical Co2 ◽

Tangential Direction ◽

Effect Of Temperature ◽

Eucalyptus Wood ◽

Conventional Kiln Drying ◽

Effects Of Temperature ◽

Temperature And Pressure ◽

Capillary Tension ◽

Increasing Temperature

Supercritical CO2 (SuCO2) dewatering can mitigate capillary tension and reduce wood collapse. In this study, Eucalyptus urophylla × E. grandis specimens were dewatered by SuCO2 at temperatures of 35, 40 and 55 °C, in pressures of 10 and 30 MPa, respectively, for 1h. Effects of temperature and pressure on dewatering rate, moisture content (MC) distribution and gradient, shrinkage and residual stress of wood after dewatering were investigated. The results indicate that the SuCO2 dewatering rate is much faster than that of conventional kiln drying (CKD). The dewatering rate increases with increasing of temperature and pressure; however, pressure has a significant influence, especially for the high-temperature dewatering process; the MC distribution after 1 h dewatering is uneven and MC gradients decrease with reducing of mean final MC of wood. MC gradients along radial direction are much smaller than that in tangential direction; collapse of wood significantly reduces after dewatering due to SuCO2 decreasing the capillary tension, and residual stress of wood during dewatering is mainly caused by pressure of SuCO2, which decreases with increasing temperature. SuCO2 dewatering has great potential advantages in water-removal of wood prone to collapse or deformation.

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The Influence of Drying Temperatures and Methods on the Drying Characteristics of ‘IkanBakar’ Paste

Journal Of Agrobiotechnology ◽

10.37231/jab.2021.12.1s.276 ◽

2021 ◽

Vol 12 (1S) ◽

pp. 112-123

Author(s):

Che Ku Nur Ain Mardhiah Che Ku Azman ◽

Mohd Tarmizan Ibrahim

Keyword(s):

Vacuum Drying ◽

Drying Rate ◽

Drying Methods ◽

Suitable Model ◽

Drying Method ◽

Time Data ◽

Drying Time ◽

Drying Characteristics ◽

Oven Drying ◽

Drying Curve

Drying is one of the popular preservation methods in food products. This work was done to investigate the influence of the drying temperatures and methods on the drying characteristics of ‘ikanbakar’ paste. The ‘ikanbakar’ paste was dried by using oven drying and vacuum drying methods at temperatures of 50°C, 60°C and 70°C. The drying rate was estimated from the moisture content and drying time data. The drying curve showed the falling rate period as the drying rate decreased with increasing time. For colour analysis of the paste, the L* values from the oven drying method were lower than those from the vacuum drying method, ranging from 7.4210 to 7.2752. This showed that the colour of paste from oven drying was darker than vacuum drying. The mathematical models used to describe the drying curve of ‘ikanbakar’ paste were Lewis, Page, Two-term, and Midilliet. al. model. The performance of these models was evaluated by comparing their root mean square error (RSME) and chi-square (X²) values, and it was found that the most suitable model was the Two-term model. There were insignificant differences between the effective moisture diffusivity (Deff) values for the ‘ikanbakar’ paste in both drying methods.

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Drying Characteristics and Physical and Nutritional Properties of Shrimp Meat as Affected by Different Traditional Drying Techniques

International Journal of Food Science ◽

10.1155/2016/7879097 ◽

2016 ◽

Vol 2016 ◽

pp. 1-5 ◽

Cited By ~ 29

Author(s):

P. T. Akonor ◽

H. Ofori ◽

N. T. Dziedzoave ◽

N. K. Kortei

Keyword(s):

Ash Content ◽

Moisture Loss ◽

Drying Methods ◽

Moisture Removal ◽

Solar Drying ◽

Nutritional Properties ◽

Drying Characteristics ◽

Red Color ◽

Drying Techniques

The influence of different drying methods on physical and nutritional properties of shrimp meat was investigated in this study. Peeled shrimps were dried separately using an air-oven dryer and a tunnel solar dryer. The drying profile of shrimp meat was determined in the two drying systems by monitoring moisture loss over the drying period. Changes in color, proximate composition, and rehydration capacity were assessed. The rate of moisture removal during solar drying was faster than the air-oven drying. The development of red color during drying was comparable among the two methods, but solar-dried shrimps appeared darker (L⁎=47.4) than the air-oven-dried (L⁎=49.0). Chemical analysis indicated that protein and fat made up nearly 20% and 2% (wb) of the shrimp meat, respectively. Protein and ash content of shrimp meat dried under the two dryer types were comparable but fat was significantly (p<0.05) higher in oven-dried meat (2.1%), compared to solar-dried meat (1.5%). Although rehydration behavior of shrimp from the two drying systems followed a similar pattern, solar-dried shrimp absorbed moisture more rapidly. The results have demonstrated that different approaches to drying may affect the physical and nutritional quality of shrimp meat differently.

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Preparation of WO3 aerogel catalysts using supercritical CO2 drying

Journal of Non-Crystalline Solids ◽

10.1016/j.jnoncrysol.2004.06.045 ◽

2004 ◽

Vol 350 ◽

pp. 308-313 ◽

Cited By ~ 12

Author(s):

Zoran Novak ◽

Petra Kotnik ◽

Željko Knez

Keyword(s):

Supercritical Co2 ◽

Supercritical Co2 Drying

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A MOISTURE STRESS INDEX FOR WHEAT BY MEANS OF A MODULATED SOIL MOISTURE BUDGET

Canadian Journal of Plant Science ◽

10.4141/cjps68-101 ◽

1968 ◽

Vol 48 (5) ◽

pp. 535-544 ◽

Cited By ~ 2

Author(s):

A. R. Mack ◽

W. S. Ferguson

Keyword(s):

Soil Moisture ◽

Stress Function ◽

Potential Evapotranspiration ◽

Moisture Stress ◽

Moisture Distribution ◽

Stress Index ◽

Wheat Crop ◽

Moisture Budget ◽

Dough Stage ◽

Soil Moisture Budget

Actual evapotranspiration (AE), soil moisture distribution, and moisture stress for a wheat crop (PE-AE) were estimated by the modulated soil moisture budget of Holmes and Robertson. The estimated soil moisture was reasonably well correlated with soil moisture measured weekly by means of gypsum blocks. Wheat yields from experimental plots in the corresponding area were related more closely to the moisture stress function (PE-AE: r = − 0.83), than to the seasonal precipitation (r = 0.62), the potential evapotranspiration (PE) or the evapotranspiration ratio (AE/PE). Regression analyses showed that the grain yields were reduced by an average of 156 (±sb = 40) kg/ha per cm of moisture stress from emergence to harvest, or by 311 and 69 kg/ha per cm of stress, from the fifth-leaf to the soft-dough stage and from the soft-dough stage to maturity, respectively. The moisture stress function may be used to characterize the soil–plant–atmosphere environment for the growing season of a crop. Precipitation and evapotranspiration data are presented annually for three standardized growing periods at Brandon from 1921 to 1963.

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